Device to prevent clogging of screens



Aug. 22,

1944. A, KARDO'S 2,356,323

DEVICE TO PREVENT CLOGGING OF SCREENS Filed March 7. 1942 I II #4194 I II III I I 4 IIIIIII" I r INVEN TOR. ANDREW KA R005 AT TORNEY Patented Aug. 22, 1944 l STATES PATENT OFFICE DEVICE 'ro. PREVENT CLOGGING F SCREENS,

Andrew Kardos, Paterson, N. J.' Application March '7, 1942, Serial No. 433,735

' 1 Claim. (,c 209 ss5) This invention relates to a device used to prevent clogging of the slots Ofseparating screens and also used to keep the screen perfectly clean and clear durin its separating operation. Its

object is to provide means to eject upwards, out

of the screen, any pieces larger than those intend-ed to pass through and those smaller than intended to stand over the slots of the screen, to enable them to pass through the intended separating process.

In many industrial processes where goods of slightly differing sizes have to be separated, this separation is being doneby means of perforated sheets, usually made of metal, and called screens. The perforations (slots) on these screens are arranged in some dense chess-board pattern and the shapes and measurements of the slots are made corresponding vto'the shapes and measurements of the goods to be separated. In separating grain the slots, are oblong, grain-shaped; in

neath have gradually smaller slots, in order to separate pieces of several decreasing sizes.

In most cases, the material to be separated is poured on the screen; pieces smaller than the slots pass through the slots by gravity; those larger than the slots remain over the screen. Borderline pieces are the mischief-makers. They cannot pass through the slot, but are forced by the flow of material and because of their shape, to enter into the slot with their thin end, while their thicker part will jam in the slot or settle above the same. Such sticking pieces (grains, gravels, etc.) will clog the slot and when enough slots are clogged the separating screen becomes ineffective. The screen will act as if it were a full metal plate, since all or most of the slots will be clogged up; no pieces will be able to pass through and even the small pieces which should be eliminated will be mixed with the larger onesthe contrary of what has been intended.

Attempts to solve this problem have not given satisfaction.

The invention consists of a scraper attached to the frame of the machine operating by spring action while the scraper and screen move relatively to each other on the under-surface of the screen, to push pieces out of the slots in the event they get stuck in them.

The invention will be further described in connection with several embodiments thereof shown in the drawing and will be finally pointed out in the claim.

In the accompanying drawing,

Figure 1 is a perspective view of a portion of a grain cleaning machine with this invention applied thereto.

Figure 2 is a detail view in elevation of one of the scrapers in Figure 1,

Figure 3 is a sectional view of the scrapers taken on line 33 of Figure 2,

Figure 4 is a sectional view on line 4-4 of Figure 3,

Figure 5 is a detail View in elevation of a scraper in operation,

Figure 6 is a sectional detail View of Figure 5 showing in operation in respect to a grain caught in the perforation, and 1 Figure 7 is a sectional detail View of a modified form of the scraper.

Similar characters indicate corresponding parts.

Referring to the drawing, there isa moving frame 5, to which the scraper is attached A stationary metal screen 6 has supplied thereon a quantity of grains.

In Figure 1, I have shown a form of mounting of the scraper device on the frame. The scraper device consists of a sheet metal forming a casing 9 holding a block [0. This block I0 is inserted into the casing from the bottom into the upward direction. There art two grooves Illa cut out on either side of the wooden block l0, up to about of the length of the block with curved portions Hlb engaged by screws I3 so as to prevent the block from jumping out of the casing 9. Two springs II are arranged at the bottom of the block Ill entering recesses I 2 thereof, the free ends of the springs abutting against the frame 5 as shown in Figure 5.

One wall M of the casing extends downwardly so as to be parallel with one side l5 of the frame 5, and has openings IE to permit the passage of screws or nails to fasten that wall to the frame 5. The opposite wall I! has its lower part I8 bent at right angles to be parallel with the upper surface IQ of the frame 5, and has openings 20 for the passage of screws and nails to fasten that wall to the block. Preferably the casing 9 is formed of the two side walls l4 and I1 and parallel with each other, and these are held in spaced position at a distance slightly larger than the width of the block In. At each end of the sidewalls shorted brackets like bands 2| and 22, are fastened to the side-Walls with rivets 9a to complete the casing. The casing however can be constructed in various manners.

The screen 6 is theoretically level, but in practical use the plane of the screen inclines in one or the other direction and varies in its different parts. The block or piston 10 is yieldingly supported to exert an upward pressure upon the lower surface of the screen, and the piston or block I0 is yieldable at either end thereof; thereby the operative surface of the piston block readily adapts itself to the plane of the screen. If new a grain or other material should be stuck in any perforation, it will be met by the surface of the block, and due to the resilient action of the block, it will be pushed upwardly and out of the perforation so as to be disengaged therefrom, to enable it to mingle with other grains and either pass through another slot, or move off that screen to be gathered in containers for that size of screen. Though that particular grain may have been blocked in one slot, it may pass through another slot of generally the same size, if it happens to confront that slot with its thinner configuration.

The operative surface of the piston block In is flat when first put to use, but being preferably of hard wood it gradually wears into the rounded form 30 shown in Fig. 6. In Figure 6 is also the resultant piston block lflc to a protruding grain stock in the slot. The cam action ejects the grain 3| through the perforation 32 of the screen 6. The general plane of the screen 6 is horizontal and the general movement of the piston is perpendicular thereto.

To prevent any piece entering between the casing wall and the block H], the end of the block l may be provided with a widened portion 35 to cover the spaces 36 betweenthe block and the casing. The widened portion 35 may be a separate piece suitably secured to the block [0 itself by a dovetail connection 31, or made integral, in which latter case, slight changes in the construction of the piston block become necessary.

In Figure 5 is shown the angular relationship of the top plane of the operative surface of the piston block In and the variable planes of the bottom of the screen 6. Should a grain protrude into the space between the surface of the screen 6 and the top surface of the block, while these surfaces are spaced from each other, the self alignment action of the spring activated piston block ID to adjust itself to the plane of the lower surface of the screen, will push the grain so as to relieve it of its clogging action.

It will have been seen that in the present invention the action of the piston member is at the bottom of the screen and that the piston member is made of a hard material, and the coaction of such a hard and rigid material with the grains brings about the separation of the grain from the screen, if the grain be stuck or clogged therein. The piston block is preferably of wood, but a plastic, or any other rigid material can be used, in contrast to a soft material such as felt or leather, which would enable a shock action to be utilized.

' I have'described several forms of my invention, but obviously various changes may be made in the details disclosed without departing from the spirit of the invention as set out in the following claim.

What I claim is: In a. device to prevent clogging metal screens having slots, a metal screen having slots moving in its longitudinal direction, a stationary frame below the screen, and a casing secured to the frame, having side and end walls and having an open top end, the combination of a piston block of hard material vertically movable in said casing and extending above the open top and having the upper part of its end walls spaced from the end walls of said casing, and having the lower part of its end walls extending to the end walls of said casing, the top of the piston having inclined walls in respect to the longitudinal direction of the sieve, springs acting upon the lower side of the piston and secured to the frame to push the piston upwardly, and means extending inwardly of the end walls of the casing against the end walls of the piston above the part of the piston extending to the end walls, whereby said means limit the upward movement of said piston, the spaced end walls of the piston permit an angular movement of the piston, and the inclined walls of the top of the piston act upon any material clogged in the slots of the sieve to eject the same upwardly of the slots of the sieve,

' ANDREW KARDOS. 

